PDW (Platelet Distribution Width)

Variation in platelet size — elevated in activated platelet states.

What it is

PDW reflects variation in platelet size. Like RDW for red cells, a high PDW indicates heterogeneous platelet production — often associated with platelet activation, inflammation, or reactive thrombocytosis.

Why it matters

Elevated PDW has been studied as an inflammatory marker and prognostic indicator in some cancer types. It is less clinically actionable than PLT or MPV alone, but contributes to the complete platelet picture.

How to test

Full blood count.

This information is for educational purposes only. Always discuss testing and interpretation of results with your care team.

Optimal range

9–17%.

How often

Each blood count panel.